1. Field of the Invention
The present invention relates to an ejector with multi-ejection pins, and particularly relates to an ejector with multi-ejection pins for lifting a plurality of dies outwardly in order to them separate from adhesive film.
2. Background of the Invention
IC (Integrated circuit) package assembly is the downstream supply of the IC industry. A wafer is separated from individual dies after the pre-processes are completed, and the dies are disposed on respective die pads arranged on a carrier adhesive tape for wrapping. The IC package assembly provides functions of environmental resistance, die support, electric conduction and further heat dissipation to increase an additional value of the IC product.
Behind a fabricated wafer is an adhesive film (a so-called ‘blue adhesive film’) for die mounting. The blue adhesive film keeps the sawed wafer (individual dies) arranged regularly. During the die bonding procedure, the individual dies are separated and removed from the blue adhesive film individually for post-processes. The individual dies are put on respective lead frames sequentially and are secured with silver epoxy. Each of the individual dies is attached to the respective die pad of the lead frame, which extends inner leads and outer leads. The carrier adhesive film is reeled in advance and fed in the lead frames (die pads). Before the dies are put onto the die pad, the silver epoxy is dispensed in advance on the die pad; the dies are lifted in turn by an ejector with only a single ejector pin to remove from the blue adhesive film. They are further picked by the pick and place machine in order to be stuck onto the die pads, respectively.
A rapid pick and place mechanism is the key technology in die bonding equipments or die array machines. Because of the various sizes and various positions of the die pads of the different carrier adhesive films, the rapid pick and place mechanism should match the carrier adhesive film with different designs in order to deliver and orientate the dies onto the respective die pads. A lift of the die is the key point of the rapid pick and place mechanism, because the die's pitch is short and the die is brittle, the lift force needs to be carefully controlled to avoid damaging the die. A more recent method to prevent the die from cracking is reading the wafer test result directly to judge whether or not the die has been ejected, thereby increasing the efficiency of the die bonding process.
With respect to TW Patent No. 298667, a die ejector having an inhalation body with a die pad is disclosed. An ejection pin is arranged inside the inhalation body. The inhalation body and the ejection pin are driven individually by first and second motors alternatively for ascent and descent. However, this conventional device can only single arrange one pin at a time and as such is incompatible with mass production methods. Additionally, the conventional device is obviously complicated and huge and a number of the devices used for lifting multiple dies cannot operate together simultaneously.
With respect to TW Patent No. 470210, a die ejector is disclosed with two ejecting sections, one of which is a pre-ejection section. This conventional device makes the ejecting motion more stable and higher and further protects the lifted die. This conventional device can also only arrange a single pin at a time and as such is incompatible with mass production methods.
The die throughput of the die bonding equipment or the die array machine is more than 8000˜10000 pieces per unit time. For mass production, if a plurality of dies can be rapidly picked and placed simultaneously, the process will be more commercially beneficial.
Hence, an improvement over the prior art is required to overcome the disadvantages thereof.